/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/**
 * @file
 * Ethernet Interface for standalone applications (without RTOS) - works only for
 * ethernet polling mode (polling for ethernet frame reception)
 *
 * This file modified by Tenkiv, Inc.
 * @since v1.0.0.0
 */

#include "lwip/opt.h"
#include "lwip/mem.h"
#include "netif/etharp.h"
#include "ethernetif.h"
#include "stm32f4x7_eth.h"
#include "stm32f4xx.h"
#include "Tekdaqc_BSP.h"
#include "eeprom.h"
#include <string.h>

/* Network interface name */
#define IFNAME0 'S'
#define IFNAME1 'T'

/* Ethernet Rx & Tx DMA Descriptors */
extern ETH_DMADESCTypeDef DMARxDscrTab[ETH_RXBUFNB], DMATxDscrTab[ETH_TXBUFNB];

/* Ethernet Driver Receive buffers  */
extern uint8_t Rx_Buff[ETH_RXBUFNB][ETH_RX_BUF_SIZE];

/* Ethernet Driver Transmit buffers */
extern uint8_t Tx_Buff[ETH_TXBUFNB][ETH_TX_BUF_SIZE];

/* Global pointers to track current transmit and receive descriptors */
extern ETH_DMADESCTypeDef *DMATxDescToSet;
extern ETH_DMADESCTypeDef *DMARxDescToGet;

/* Global pointer for last received frame infos */
extern ETH_DMA_Rx_Frame_infos *DMA_RX_FRAME_infos;

/**
 * In this function, the hardware should be initialized.
 * Called from ethernetif_init().
 *
 * @param netif the already initialized lwip network interface structure
 *        for this ethernetif
 */
static void low_level_init(struct netif *netif) {
#ifdef CHECKSUM_BY_HARDWARE
	int i;
#endif
	/* set MAC hardware address length */
	netif->hwaddr_len = ETHARP_HWADDR_LEN;

	/* set MAC hardware address */
	uint8_t M0, M1, M2, M3, M4, M5;
	uint16_t isUserMacValid = 0;
	EE_ReadVariable(ADDR_USE_USER_MAC, &isUserMacValid);
	if (isUserMacValid != 0) {
		/* We should program the user MAC address */
		uint16_t low, mid, high;
		EE_ReadVariable(ADDR_USER_MAC_LOW, &low);
		EE_ReadVariable(ADDR_USER_MAC_MID, &mid);
		EE_ReadVariable(ADDR_USER_MAC_HIGH, &high);
		/* The high bytes are the first bytes in the MAC address from the perspective of the user */
		M0 = (high >> 8) & 0xFF;
		M1 = high & 0xFF;
		M2 = (mid >> 8) & 0xFF;
		M3 = mid & 0xFF;
		M4 = (low >> 8) & 0xFF;
		M5 = low & 0xFF;
	} else {
		/* We should try to use the factory programmed MAC Address */
		M0 = *((uint8_t *) FACTORY_MAC_ADDR0);
		M1 = *((uint8_t *) FACTORY_MAC_ADDR1);
		M2 = *((uint8_t *) FACTORY_MAC_ADDR2);
		M3 = *((uint8_t *) FACTORY_MAC_ADDR3);
		M4 = *((uint8_t *) FACTORY_MAC_ADDR4);
		M5 = *((uint8_t *) FACTORY_MAC_ADDR5);

		if (M0 == 0xFF && M1 == 0xFF && M1 == 0xFF && M2 == 0xFF && M3 == 0xFF && M4 == 0xFF && M5 == 0xFF) {
			/* We should use the default hard coded MAC address */
			M0 = MAC_ADDR0;
			M1 = MAC_ADDR1;
			M2 = MAC_ADDR2;
			M3 = MAC_ADDR3;
			M4 = MAC_ADDR4;
			M5 = MAC_ADDR5;
		}
	}
	netif->hwaddr[0] = M0;
	netif->hwaddr[1] = M1;
	netif->hwaddr[2] = M2;
	netif->hwaddr[3] = M3;
	netif->hwaddr[4] = M4;
	netif->hwaddr[5] = M5;

	/* initialize MAC address in ethernet MAC */
	ETH_MACAddressConfig(ETH_MAC_Address0, netif->hwaddr);

	/* maximum transfer unit */
	netif->mtu = 1500;

	/* device capabilities */
	/* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
	netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP;

	/* Initialize Tx Descriptors list: Chain Mode */
	ETH_DMATxDescChainInit(DMATxDscrTab, &Tx_Buff[0][0], ETH_TXBUFNB);
	/* Initialize Rx Descriptors list: Chain Mode  */
	ETH_DMARxDescChainInit(DMARxDscrTab, &Rx_Buff[0][0], ETH_RXBUFNB);

#ifdef CHECKSUM_BY_HARDWARE
	/* Enable the TCP, UDP and ICMP checksum insertion for the Tx frames */
	for (i = 0; i < ETH_TXBUFNB; i++) {
		ETH_DMATxDescChecksumInsertionConfig(&DMATxDscrTab[i], ETH_DMATxDesc_ChecksumTCPUDPICMPFull);
	}
#endif

	/* Note: TCP, UDP, ICMP checksum checking for received frame are enabled in DMA config */

	/* Enable MAC and DMA transmission and reception */
	ETH_Start();

}

/**
 * This function should do the actual transmission of the packet. The packet is
 * contained in the pbuf that is passed to the function. This pbuf
 * might be chained.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
 * @return ERR_OK if the packet could be sent
 *         an err_t value if the packet couldn't be sent
 *
 * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
 *       strange results. You might consider waiting for space in the DMA queue
 *       to become availale since the stack doesn't retry to send a packet
 *       dropped because of memory failure (except for the TCP timers).
 */

static err_t low_level_output(struct netif *netif, struct pbuf *p) {
	err_t errval;
	struct pbuf *q;
	u8 *buffer = (u8 *) (DMATxDescToSet->Buffer1Addr);
	__IO ETH_DMADESCTypeDef *DmaTxDesc;
	uint16_t framelength = 0;
	uint32_t bufferoffset = 0;
	uint32_t byteslefttocopy = 0;
	uint32_t payloadoffset = 0;

	DmaTxDesc = DMATxDescToSet;
	bufferoffset = 0;

	/* copy frame from pbufs to driver buffers */
	for (q = p; q != NULL; q = q->next) {
		/* Is this buffer available? If not, goto error */
		if ((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (u32) RESET) {
			errval = ERR_BUF;
			goto error;
		}

		/* Get bytes in current lwIP buffer */
		byteslefttocopy = q->len;
		payloadoffset = 0;

		/* Check if the length of data to copy is bigger than Tx buffer size*/
		while ((byteslefttocopy + bufferoffset) > ETH_TX_BUF_SIZE) {
			/* Copy data to Tx buffer*/
			memcpy((u8_t*) ((u8_t*) buffer + bufferoffset), (u8_t*) ((u8_t*) q->payload + payloadoffset),
					(ETH_TX_BUF_SIZE - bufferoffset));

			/* Point to next descriptor */
			DmaTxDesc = (ETH_DMADESCTypeDef *) (DmaTxDesc->Buffer2NextDescAddr);

			/* Check if the buffer is available */
			if ((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (u32) RESET) {
				errval = ERR_USE;
				goto error;
			}

			buffer = (u8 *) (DmaTxDesc->Buffer1Addr);

			byteslefttocopy = byteslefttocopy - (ETH_TX_BUF_SIZE - bufferoffset);
			payloadoffset = payloadoffset + (ETH_TX_BUF_SIZE - bufferoffset);
			framelength = framelength + (ETH_TX_BUF_SIZE - bufferoffset);
			bufferoffset = 0;
		}

		/* Copy the remaining bytes */
		memcpy((u8_t*) ((u8_t*) buffer + bufferoffset), (u8_t*) ((u8_t*) q->payload + payloadoffset), byteslefttocopy);
		bufferoffset = bufferoffset + byteslefttocopy;
		framelength = framelength + byteslefttocopy;
	}

	/* Note: padding and CRC for transmitted frame
	 are automatically inserted by DMA */

	/* Prepare transmit descriptors to give to DMA*/
	ETH_Prepare_Transmit_Descriptors(framelength);

	errval = ERR_OK;

	error:

	/* When Transmit Underflow flag is set, clear it and issue a Transmit Poll Demand to resume transmission */
	if ((ETH->DMASR & ETH_DMASR_TUS) != (uint32_t) RESET) {
		/* Clear TUS ETHERNET DMA flag */
		ETH->DMASR = ETH_DMASR_TUS;

		/* Resume DMA transmission*/
		ETH->DMATPDR = 0;
	}
	return errval;
}

/**
 * Should allocate a pbuf and transfer the bytes of the incoming
 * packet from the interface into the pbuf.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return a pbuf filled with the received packet (including MAC header)
 *         NULL on memory error
 */
static struct pbuf * low_level_input(struct netif *netif) {
	struct pbuf *p, *q;
	uint32_t len;
	FrameTypeDef frame;
	u8 *buffer;
	__IO ETH_DMADESCTypeDef *DMARxDesc;
	uint32_t bufferoffset = 0;
	uint32_t payloadoffset = 0;
	uint32_t byteslefttocopy = 0;
	uint32_t i = 0;

	/* get received frame */
	frame = ETH_Get_Received_Frame();

	/* Obtain the size of the packet and put it into the "len" variable. */
	len = frame.length;
	buffer = (u8 *) frame.buffer;

	/* We allocate a pbuf chain of pbufs from the Lwip buffer pool */
	p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);

	if (p != NULL) {
		DMARxDesc = frame.descriptor;
		bufferoffset = 0;
		for (q = p; q != NULL; q = q->next) {
			byteslefttocopy = q->len;
			payloadoffset = 0;

			/* Check if the length of bytes to copy in current pbuf is bigger than Rx buffer size*/
			while ((byteslefttocopy + bufferoffset) > ETH_RX_BUF_SIZE) {
				/* Copy data to pbuf*/
				memcpy((u8_t*) ((u8_t*) q->payload + payloadoffset), (u8_t*) ((u8_t*) buffer + bufferoffset),
						(ETH_RX_BUF_SIZE - bufferoffset));

				/* Point to next descriptor */
				DMARxDesc = (ETH_DMADESCTypeDef *) (DMARxDesc->Buffer2NextDescAddr);
				buffer = (unsigned char *) (DMARxDesc->Buffer1Addr);

				byteslefttocopy = byteslefttocopy - (ETH_RX_BUF_SIZE - bufferoffset);
				payloadoffset = payloadoffset + (ETH_RX_BUF_SIZE - bufferoffset);
				bufferoffset = 0;
			}
			/* Copy remaining data in pbuf */
			memcpy((u8_t*) ((u8_t*) q->payload + payloadoffset), (u8_t*) ((u8_t*) buffer + bufferoffset),
					byteslefttocopy);
			bufferoffset = bufferoffset + byteslefttocopy;
		}
	}

	/* Release descriptors to DMA */
	DMARxDesc = frame.descriptor;

	/* Set Own bit in Rx descriptors: gives the buffers back to DMA */
	for (i = 0; i < DMA_RX_FRAME_infos->Seg_Count; i++) {
		DMARxDesc->Status = ETH_DMARxDesc_OWN;
		DMARxDesc = (ETH_DMADESCTypeDef *) (DMARxDesc->Buffer2NextDescAddr);
	}

	/* Clear Segment_Count */
	DMA_RX_FRAME_infos->Seg_Count = 0;

	/* When Rx Buffer unavailable flag is set: clear it and resume reception */
	if ((ETH->DMASR & ETH_DMASR_RBUS) != (u32) RESET) {
		/* Clear RBUS ETHERNET DMA flag */
		ETH->DMASR = ETH_DMASR_RBUS;
		/* Resume DMA reception */
		ETH->DMARPDR = 0;
	}
	return p;
}

/**
 * This function should be called when a packet is ready to be read
 * from the interface. It uses the function low_level_input() that
 * should handle the actual reception of bytes from the network
 * interface. Then the type of the received packet is determined and
 * the appropriate input function is called.
 *
 * @param netif the lwip network interface structure for this ethernetif
 */
err_t ethernetif_input(struct netif *netif) {
	err_t err;
	struct pbuf *p;

	/* move received packet into a new pbuf */
	p = low_level_input(netif);

	/* no packet could be read, silently ignore this */
	if (p == NULL)
		return ERR_MEM;

	/* entry point to the LwIP stack */
	err = netif->input(p, netif);

	if (err != ERR_OK) {
		LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
		pbuf_free(p);
	}
	return err;
}

/**
 * Should be called at the beginning of the program to set up the
 * network interface. It calls the function low_level_init() to do the
 * actual setup of the hardware.
 *
 * This function should be passed as a parameter to netif_add().
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return ERR_OK if the loopif is initialized
 *         ERR_MEM if private data couldn't be allocated
 *         any other err_t on error
 */
err_t ethernetif_init(struct netif *netif) {
	LWIP_ASSERT("netif != NULL", (netif != NULL));

#if LWIP_NETIF_HOSTNAME
	/* Initialize interface hostname */
	netif->hostname = "lwip";
#endif /* LWIP_NETIF_HOSTNAME */

	netif->name[0] = IFNAME0;
	netif->name[1] = IFNAME1;
	/* We directly use etharp_output() here to save a function call.
	 * You can instead declare your own function an call etharp_output()
	 * from it if you have to do some checks before sending (e.g. if link
	 * is available...) */
	netif->output = etharp_output;
	netif->linkoutput = low_level_output;

	/* initialize the hardware */
	low_level_init(netif);

	return ERR_OK;
}
